Law and Chaos 

In some S&S universes, most notably Michael Moorcock’s, the forces of Law and Chaos are very active. They are ideological super-powers claiming to be the manifestations of the ruling and guiding principles of the universe. They are not notably good or evil but given over to more pragmatic realpolitik, helping those that support them. You can use Law and Chaos as the primary alignments of your universe. You probably should not use good and evil in the conventional D&D sense if you do. 

Alignment Requirements 

Obviously when you are not using alignments, you can forget about alignment restrictions for most things or you can replace them with the rules for taint given below. 

If you want to use prestige classes that use alignment requirements, you should consider using tests instead. In order to join the prestige class the character will have to perform an appropriate deed or quest instead. To become an assassin you may have to kill a target selected by the Guildmaster for example. Obviously the test should require the sort of behaviour an organisation expects of its members.

The Taint of Evil 

Supernatural power tends to warp the minds and bodies of mages in S&S worlds. Any character possessing the Taint will show up on a detect evil spell and be affected by spells that affect evil. 

Taint points are simply a measure of how corrupted a character has become in body, mind or spirit from the use of magic. In some worlds they might represent the results of exposure to the warping chaotic energies of magic, in others they may represent the spirit poisoning power of the dark forces of sorcery. In any case, they represent exposure to magical “radiation” as it were, and the resulting effects.

Acquiring Taint Points by Magic 

There are several variant methods of acquiring taint points. As a DM you should decide in advance which one you want to use.

Paying A Terrible Price for Forbidden Knowledge. (Use this variant in a world where magic is powerfully warping to mind or spirit.) Whenever you gain the ability to cast a higher level of spells than previously you gain a taint point. You can never have less taint points than the highest level of spell you can cast.

Tainted Power. In this variant the knowledge of magic is not tainted, but drawing on its power is. Whenever a magician casts a spell of higher level than his taint score he gains a point of taint. This can be removed by the usual means but it will come back the next time a spell of higher level than the new taint score is used. One variant of this is to allow the magician a Will or Fortitude saving throw to avoid the taint with a DC equal to 10+ the spell level. Another possibility is that only some spells have the taint effect. These might include evil spells and spells that cause physical damage and harm. 

Magical Taint Levels 

It is possible to set the default level of taint at different levels ranging from -9 to +9. The magical taint level is added to the taint level where appropriate to find out the affects of taint. In forbidden knowledge worlds magic may not cause taint until you start casting 3rd level spells. This would be written as taint level-2. Heavily tainted worlds might immediately give you a higher level of taint. Taint level +1 would mean you would get 1 taint point as soon as you acquired zero level spells, 2 when you got first level and so on. In tainted power worlds the taint level would be added or subtracted to the level of the spell to see whether it caused taint.